Every industry has its terminology, its “buzzwords”, and the window industry is no different. Among the most basic of this terminology are the descriptive words used to distinguish one type or style or configuration of a window from another.

Ideally, these three types of windows look very much alike because all three are used in typical homes. We refer to them as “companion windows” in the same “Series”, “Model”, or “family” of window design. Single Hung windows represent the overwhelming majority of windows in the South Central Region. The term refers to the design feature of a single sash hung in a frame. Some older designs allow for no removal of the sash once it is set inside the frame jambs. Others allow the sash to be taken out (“take-out sash” or “side-load sash”), but not tilted. More popular designs feature tilt options that enable the sash to be tilted inwards for easy cleaning and screen access from inside the home.

The single slider window can be thought of as its companion single hung laid
on its side. While hung window sash are fitted with counterbalances that make
lifting them easy, the slider sash rolls on small wheels. The “OX” refers to
the operation of the sash, where the “X” is the operating sash and the “O” does
not move. Our only perspective is from the outside of the home looking inward.
So on this OX slider depicted, if it were in your bathroom you would open the
left sash from left to right. Most sliders are designed to allow easy removal
of the sash from inside, but do not tilt. Generally, sliders are very popular
in the Western Region, and are used in other regions mostly as bathroom windows
or in a kitchen where they are easily slid open.

Picture Windows are sometimes referred to as Fixed-Lite windows because you cannot open them. Like a picture frame, these windows have no sash and consist of glass and frame. Because they have no sash, picture windows easily outperform any hung or sliding window in terms of air and water infiltration.

Double Hung windows are the mainstay of the wood window industry and have become
the standard for replacement windows in most areas of the country. The term refers
to the design feature of both sashes hung in a frame. Some older designs allow
for no removal of the sash once it is set inside the frame jambs. Others allow
the sash to be taken out (“take-out sash” or “side-load sash”), but not tilted. More popular designs feature tilt options that enable the sashes to be tilted inwards for easy cleaning of both sashes and screen access from inside the home.

The double slider window can be thought of as its companion double hung laid
on its side. While hung window sashes are fitted with counterbalances that make
lifting them easy, the slider sashes roll on small wheels. The “XX” refers
to the operation of the sash, where both “X” sashes slide. Most sliders are designed
to allow easy removal of the sash from inside, but do not tilt. Generally, sliders
are very popular in the Western Region, and are used in other regions mostly
as bathroom windows or in a kitchen where they are easily slid open.

Picture Windows are sometimes referred to as Fixed-Lite windows because you cannot open them. Like a picture frame, these windows have no sash and consist of glass and frame. Because they have no sash, picture windows easily outperform any hung or sliding window in terms of air and water infiltration. These windows are the type most frequently bent into geometric shapes.

Comparative Note:
We can help manage your expectations as to which generic window type has the
best resistance to air and water penetration of your home. Think about the physical
fact that energy follows the path of least resistance. Knowing this, the window
with the least opportunities for such paths is the window with no operating sash,
or the fixed-lite window. On the other extreme is the window with the most opportunities
for paths, or the double hung window. This is because each sash has four undersized
edges that hang removed from and inside the frame, separated only by a gasket
system called “weather stripping” . It is the weather stripping that makes the
difference in such designs between leaks and no leaks, and our industry has produced
many ways to properly seal these otherwise exposed edges of sash. In between
are all the other window types. Recognizing that there are exceptions to this
generalization, in order of best to worst resistance to air and water infiltration
by window design:

Picture Windows or Fixed-Lite

Casement Windows

Single Hung

Single Slider

Double Hung

Double Slider

Whether different or the same type of window, they can be assembled together in a wide variety of ways. When we attach one window on top of another, it is called “stacked”. When we attach one window beside another, it is called “mulled” or “mulling”. A “twin” window is two mulled together; a “triple” is three, a “quad” four. Some stacking and mulling requires a “mull bar” that works with sealant to ensure a tight fit. Other systems require no bars, and some are able to mull or stack different types of windows all in the same frame. Some mulled or stacked assemblies can be so big and heavy and dangerous to transport that the final assembly must be accomplished in the field and cannot be done on the factory floor.

If there were an “elite” award for the ultimate operating window design, casement windows would win it. Casements are always in style and very popular with people who want the uninterrupted view of a picture window with the function of an opening sash. It is simple and basic, a sash in a frame with operating hardware that “cranks” and opens the sash like a refrigerator door. The harder the window blows against a casement sash, the tighter it seals against its frame. Unlike other windows, casement screens (when applied) are mounted inside the frame. Casements are frequently stacked and/or mulled together to form a number of configurations, including Bays and Bows. Our only perspective is from the outside of the home looking inward. So this “left hinged” operating casement depicted would crank outward from your left to right and hold the opened sash to the right of your frame from inside your house. Awning windows are like casements mounted sideways, and they differ from basement windows in that awnings open with casement hardware. Hopper windows are common in older schools and certain commercial structures, and generally have hinges like basement windows but no operating hardware.

Bays typically feature a picture window flanked by operating windows. Bows usually feature operating windows on the ends and fixed windows in between. These depictions appear to be all picture windows, but are most likely casement windows, the most popular window for bays and bows. Typically in Eastern, Northern, and Midwestern regions, bay and bow windows are made as complete modules and delivered as an assembled unit from the factory to your house. They first became popular by replacing the traditionally large, flat, single-pane picture window or slider in the front elevation of smaller ranch or bi-level style homes. Projecting outward from the inner wall and featuring a “seat” and “head” board made of wood, bays and bows make smaller living rooms feel bigger and enhance the curb appeal of such homes. In Southern Regions, bays and bows are commonly “framed into” the wall as opposed to being built as a separate module or complete insert. The windows in this type of assembly are mulled on-site. If your floor projects outwardly in the bay or bow pattern, yours is a framed-in assembly.

Most windows can be bent or shaped into geometric patterns. Picture windows and single hung windows can be made in geometric shapes to a limited degree. These shapes have become very popular over the years. We have depicted only three of what could be dozens of different shapes of different window types. Reputable window manufacturers of integrity have reasonable limits to the sizes and shapes they are willing to produce and deliver for installation into your home.